Robust Subthermionic Topological Transistor Action via Antiferromagnetic Exchange

TL;DR

This paper explores how antiferromagnetic exchange in topological materials can enable sub-thermionic transistor operation while maintaining topological robustness, addressing fundamental limits and proposing new device strategies.

Contribution

It introduces a novel approach using antiferromagnetic exchange to achieve robust topological transistor action beyond thermionic limits.

Findings

Antiferromagnetic exchange induces phase transitions ensuring topological robustness.

Gating strategies can surpass thermionic limits but may sacrifice dissipationless conduction.

Material and device innovations are necessary to optimize sub-thermionic topological transistors.

Abstract

The topological quantum field-effect transition in buckled 2D-Xenes can potentially be engineered to enable sub-thermionic transistor operation coupled with dissipationless ON-state conduction. Substantive device design strategies to harness this will necessitate delving into the physics of the quantum field effect transition between the dissipationless topological phase and the band insulator phase. Investigating workable device structures, we uncover fundamental sub-threshold limits posed by the gating mechanism that effectuates such a transition, thereby emphasizing the need for innovations on materials and device structures. Detailing the complex band translation physics related to the quantum spin Hall effect phase transition, it is shown that a gating strategy to beat the thermionic limit can be engineered at the cost of sacrificing the dissipationless ON-state conduction. It is then demonstrated that an out-of-plane antiferromagnetic exchange introduced in the material via proximity coupling can incite transitions between the quantum spin-valley Hall and the spin quantum anomalous Hall phase, which can ultimately ensure the topological robustness of the ON state while surpassing the thermionic limit. Our work thus underlines the operational criteria for building topological transistors using quantum materials that can overcome the Boltzmann's tyranny while preserving the topological robustness.